VM: [Kernel] Cherry-pick from dart-lang/kernel_sdk

runtime/vm/kernel_reader.cc

Index: runtime/vm/kernel_reader.cc
diff --git a/runtime/vm/kernel_reader.cc b/runtime/vm/kernel_reader.cc
index 7e8f6f44fb5d5b7767102883c10fd0df805a63f2..5eb64607f79fed167926edfe31ee74b45606b431 100644
--- a/runtime/vm/kernel_reader.cc
+++ b/runtime/vm/kernel_reader.cc
@@ -170,10 +170,6 @@ void KernelReader::ReadLibrary(Library* kernel_library) {
                           TokenPosition::kNoSource));
   toplevel_class.set_is_cycle_free();
   library.set_toplevel_class(toplevel_class);
-  if (bootstrapping_) {
-    GrowableObjectArray::Handle(Z, I->object_store()->pending_classes())
-        .Add(toplevel_class, Heap::kOld);
-  }
 
   ActiveClassScope active_class_scope(&active_class_, NULL, &toplevel_class);
   // Load toplevel fields.
@@ -209,6 +205,8 @@ void KernelReader::ReadLibrary(Library* kernel_library) {
     Class* kernel_klass = kernel_library->classes()[i];
     classes.Add(ReadClass(library, kernel_klass), Heap::kOld);

[Kevin Millikin (Google), 2016/11/21 15:00:11]

When bootstrapping, ReadClass is also adding classes to the pending class list. 
I guess that's safe but it does extra work and grows the pending class list too
much.

I think the only purpose of the bootstrapping_ flag was to know if we should
finalize classes more or less eagerly.  It probably isn't needed any more.

[kustermann, 2016/11/21 15:30:05]

Good point. Done.

   }
+
+  classes.Add(toplevel_class, Heap::kOld);
 }
 
 
@@ -645,7 +643,7 @@ dart::Class& KernelReader::LookupClass(Class* klass) {
     // we do not risk allocating the class again by calling LookupClass
     // recursively from ReadPreliminaryClass for the same class.
     classes_.Insert(klass, handle);
-    if (!handle->is_type_finalized()) {
+    if (!handle->is_cycle_free()) {
       ReadPreliminaryClass(handle, klass);
     }
   }